Gin is having a moment in the UK. Supermarkets can’t keep hipster micro-distilled brands on their shelves, and tourists are flocking to themed spas and hotels that celebrate the liquor’s long history. And what a history it is: Gin was long a societal scourge, blamed for addiction and depredation, until it began its slow march toward respectability—helped in large part by being paired with a bitter antimalarial drug.